Boresight tilt correction method and system based on linear accelerometer broadband vibration detection

Abstract

This application discloses a method and system for line-of-sight tilt correction based on broadband vibration detection using linear accelerometers, relating to the field of disturbance suppression in composite axis control. This invention achieves real-time automatic correction of line-of-sight errors by constructing a closed-loop control system between a piezoelectric reflector and an image sensor at the load end of a Stewart platform. Residual disturbance signals at the platform load end are acquired using two linear accelerometers, and angular velocity and angular displacement are obtained by integrating angular acceleration using a low-pass filter instead of an integrator. Subsequently, a disturbance feedforward controller generates a feedforward compensation signal through a multi-channel compensation structure, achieving segmented compensation for disturbances in different frequency bands, thereby improving the system's broadband vibration detection capability and tilt correction accuracy.

Description

Technical Field

[0001] This invention relates to the field of disturbance suppression in composite axis control, and more specifically to a method and system for line-of-sight tilt correction based on broadband vibration detection by a linear accelerometer. Background Technology

[0002] High-precision optical systems have stringent requirements for line-of-sight stability and imaging accuracy. For example, in inter-satellite or space-to-ground laser communication terminals, spaceborne optoelectronic platforms, ultra-large aperture space optical telescopes, and high-speed scanning optical systems, the beam needs to maintain high-precision and stable pointing on the moving platform. However, minute disturbances and structural vibrations are common and can significantly affect system performance. Piezoelectric mirrors are widely used in optical platforms due to their advantages such as rapid response, high precision, and compact structure, for fine-tuning the line-of-sight and achieving rapid optical path deflection. However, traditional closed-loop control relying on image sensor feedback is limited by sampling rate and processing latency, and has limited ability to suppress mid-to-high frequency disturbances, making it difficult to meet the precise pointing requirements in high-speed dynamic scenarios.

[0003] To enhance the system's ability to sense broadband vibrations, a linear accelerometer, as a highly sensitive and fast-response sensor, is introduced to detect micro-vibrations in real time across the mid- to high-frequency range. This provides precise vibration information to the piezoelectric mirror or optical platform, enabling disturbance feedforward control. By filtering, superimposing, and analyzing the accelerometer signals, the system's response to complex vibration environments can be improved, enabling rapid attitude adjustment and fine tilt correction, thereby significantly reducing the line-of-sight error of the optical system under broadband vibration conditions.

[0004] However, feedforward compensation based on linear accelerometers still has limitations: measurement noise and bias may introduce errors, and direct use for compensation can easily lead to error accumulation and drift; the synthesis calculation of angular acceleration requires high signal processing accuracy; the dependence of feedforward control on the accuracy of disturbance measurement and system modeling still exists; and the suppression effect of high-frequency disturbances is limited to a certain extent. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a line-of-sight tilt correction method and system based on broadband vibration detection using a linear accelerometer. This method fully utilizes the precise measurements of the linear accelerometer to effectively suppress broadband vibrations and significantly improve the tilt correction accuracy of the system.

[0006] The first aspect discloses a line-of-sight tilt correction method based on broadband vibration detection using a linear accelerometer, the method comprising:

[0007] The image sensor obtains a line-of-sight error signal based on the acquired target imaging information. A first and second linear accelerometer are used to collect disturbance signals from the Stewart platform load end in real time. The first and second linear accelerometers are symmetrically mounted on the platform load end, with their sensitive axes parallel and opposite in direction. The disturbance signal is a measured angular acceleration signal of the Stewart platform load, synthesized from acceleration data acquired by the first and second linear accelerometers in different directions. Based on the disturbance signal, the disturbance feedforward controller uses a preset multi-channel compensation structure to superimpose signals to obtain a feedforward compensation signal and compensate for the line-of-sight error signal. The compensated line-of-sight error signal is then used to output a corresponding control quantity to drive the piezoelectric reflector to deflect accordingly, ensuring the target remains centered in the field of view.

[0008] The second aspect discloses a line-of-sight tilt correction system based on broadband vibration detection using linear accelerometers. The system includes a Stewart platform, a piezoelectric reflector, an image sensor, a first linear accelerometer, a second linear accelerometer, a disturbance feedforward controller, and an image closed-loop controller. The image sensor is used to obtain a line-of-sight error signal based on acquired target imaging information. The first and second linear accelerometers are used to acquire disturbance signals from the load end of the Stewart platform in real time. The first and second linear accelerometers are symmetrically mounted on the load end of the platform, with their sensitive axes parallel and opposite in direction. The disturbance signal is an angular acceleration signal of the load Stewart platform motion synthesized from acceleration data acquired by the first and second linear accelerometers in different directions. The disturbance feedforward controller is used to obtain a feedforward compensation signal by superimposing the disturbance signal through a preset multi-channel compensation structure and to perform feedforward compensation on the line-of-sight error signal. The image closed-loop controller outputs a corresponding control quantity based on the compensated line-of-sight error signal to drive the piezoelectric reflector to produce a corresponding deflection, ensuring the target remains at the center of the field of view.

[0009] As can be seen from the above technical solutions, the present invention has the following beneficial effects:

[0010] This invention achieves real-time automatic correction of line-of-sight errors by constructing a closed-loop control system between a piezoelectric reflector and an image sensor at the load end of the Stewart platform. Secondly, residual disturbance signals at the platform load end are acquired using two linear accelerometers, and angular velocity and angular displacement are obtained by integrating angular acceleration using a low-pass filter instead of an integrator. Subsequently, a disturbance feedforward controller generates feedforward compensation signals through a multi-channel compensation structure, achieving segmented compensation for disturbances in different frequency bands, thereby improving the system's broadband vibration detection capability and tilt correction accuracy.

[0011] This invention overcomes the limitation of the system's closed-loop bandwidth, enabling rapid cancellation of disturbances and thus improving the system's anti-disturbance performance. The image sensor detects the residual displacement of the platform through a piezoelectric reflector optical system. By inputting the acceleration signal into the disturbance feedforward controller and coordinating with the position closed-loop control system, the influence of mid-to-high frequency disturbances on the platform is effectively suppressed, thereby improving the system's broadband disturbance suppression capability and tilt correction accuracy. Attached Figure Description

[0012] Figure 1 This is a flowchart of a line-of-sight tilt correction method based on broadband vibration detection using a linear accelerometer, according to the present invention.

[0013] Figure 2 This is a block diagram of the multi-channel disturbance feedforward control structure based on linear acceleration proposed in this invention.

[0014] Figure 3 This invention provides an architecture diagram of a line-of-sight tilt correction system based on broadband vibration detection using a linear accelerometer. Detailed Implementation

[0015] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be thorough and complete.

[0016] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0017] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "up," "down," and similar expressions used herein are for illustrative purposes only and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0018] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0019] This solution primarily addresses the broadband vibration suppression problem in high-precision optical pointing systems, and is applicable to typical applications such as space optical communication terminals, spaceborne optoelectronic platforms, space optical telescopes, and high-speed scanning optical systems. In such systems, the carrier platform is typically in motion and subjected to multi-source micro-vibration excitations from reaction flywheels, refrigerators, and structural vibrations, resulting in mid-to-high frequency line-of-sight disturbances that affect beam pointing stability. The "high-speed dynamic scenario" described in this paper refers to the aforementioned application environment with broadband micro-vibration interference and stringent requirements for line-of-sight stability accuracy.

[0020] In one embodiment, the present invention provides a line-of-sight tilt correction method based on broadband vibration detection using a linear accelerometer, such as... Figure 1 As shown, the specific steps include:

[0021] S101, The image sensor obtains the line-of-sight error signal based on the acquired target imaging information;

[0022] Specifically, the line-of-sight error signal is acquired by an optical detector, such as a CCD (Charge Coupled Device) image sensor, which detects the positional offset of the light spot on the detector surface and calculates it based on the deviation of the light spot relative to the origin O of the field of view. This deviation can be regarded as the difference between the control system setpoint and the feedback value. The control objective is to make the error approach zero and keep the target light spot always at the center of the field of view.

[0023] S102. The disturbance signal at the load end of the Stewart platform is acquired in real time by the first linear accelerometer and the second linear accelerometer. The first linear accelerometer and the second linear accelerometer are installed symmetrically at the load end of the platform, and the sensitive axes of the two linear accelerometers are parallel and opposite. The disturbance signal is the measured angular acceleration signal of the load Stewart platform motion synthesized by the acceleration data in different directions acquired by the first linear accelerometer and the second linear accelerometer.

[0024] Specifically, the number is ( Two linear accelerometers, namely the first linear accelerometer and the second linear accelerometer, are symmetrically mounted on the load end of the Stewart platform. Their sensing axes are parallel and opposite in direction, and their distance from the center of the inertial reference frame is [distance missing]. , This represents the distance between the first linear accelerometer and the center of the inertial reference frame. This indicates the distance between the second linear accelerometer and the center of the inertial reference frame.

[0025] In one embodiment, the calculation process for measuring the angular acceleration signal includes:

[0026] Obtain the measurement output results of the first linear accelerometer and the second linear accelerometer;

[0027] The measured angular acceleration signal is calculated based on the measurement output results and the distances between the first and second linear accelerometers and the center of the inertial reference frame. The distances from the first and second linear accelerometers to the center of the inertial reference frame are the same.

[0028] Specifically, suppose an amplitude of is applied to the Stewart platform. Angular frequency is sinusoidal disturbance signal The specific measurement output of the linear accelerometer is shown in the formula:

[0029] (1);

[0030] in, , , , , and They represent circumference respectively. , and angular velocity of the axis, , and This represents linear acceleration along the corresponding axis. It is the acceleration due to gravity. This indicates the direction of the sensing axis of the linear accelerometer relative to the established measurement coordinate system. The included angle of the axes, when the included angle is 0, ; The measured signals are combined and processed to obtain the measured angular acceleration signal of the load platform, as shown in the formula:

[0031] (2);

[0032] in, This indicates the measurement output of the first linear accelerometer; This indicates the measurement output of the second linear accelerometer. This represents the distance between the first linear accelerometer and the center of the inertial reference frame. This indicates the distance between the second linear accelerometer and the center of the inertial reference frame. This indicates that the distances from the first and second linear accelerometers to the center of the inertial reference frame are the same.

[0033] S103. Based on the disturbance signal, the disturbance feedforward controller obtains a feedforward compensation signal by superimposing the signal through a preset multi-channel compensation structure and performs feedforward compensation.

[0034] Specifically, based on the frequency band of the disturbance signal, a corresponding compensation channel is selected to generate a feedforward compensation signal and perform feedforward compensation on the line-of-sight error signal.

[0035] In one embodiment, the above steps include:

[0036] When the disturbance signal is in the high-frequency band, the superposition signal of the angular acceleration signal generated by the angular acceleration compensation channel, the angular velocity signal generated by the angular velocity compensation channel, and the angular displacement signal generated by the angular displacement compensation channel is used as the feedforward compensation signal;

[0037] When the disturbance signal is in the mid-frequency band, the superposition signal of the angular velocity signal generated by the angular velocity compensation channel and the angular displacement signal generated by the angular displacement compensation channel is used as the feedforward compensation signal.

[0038] When the disturbance signal is in the low frequency band, an angular displacement signal is generated through the angular displacement compensation channel and used as a feedforward compensation signal.

[0039] It should be noted that the preset multi-channel compensation structure includes an angular acceleration compensation channel, an angular velocity compensation channel, and an angular displacement compensation channel, and the three compensation channels adopt a parallel structure.

[0040] Furthermore, the construction process of the pre-defined multi-channel compensation structure specifically includes:

[0041] Based on the dynamic relationship between the disturbance signal and the line-of-sight error signal at the Stewart platform load end, a disturbance suppression transfer function is established;

[0042] The initial multi-channel compensation structure is obtained based on the disturbance suppression transfer function, wherein when the disturbance suppression transfer function is zero, complete suppression of disturbances at the load end of the Stewart platform is achieved.

[0043] The gain parameters of the initial multi-channel compensation structure are iteratively optimized to obtain a preset multi-channel compensation structure.

[0044] Specifically, firstly, a feedforward control structure based on a linear accelerometer is constructed, the schematic diagram of which is shown below. Figure 2 As shown, based on the residual disturbance at the load end of the Stewart platform Output of line of sight error Based on the dynamic relationship between them, a disturbance suppression transfer function is established, as shown in the formula:

[0045] (3)

[0046] in, This represents the measurement model of a linear accelerometer. This indicates a disturbance feedforward controller. This indicates a piezoelectric reflector controller. This represents the dynamic model of a piezoelectric reflector. Indicates the system delay component; This is a complex frequency domain operator in the Laplace transform. In control system analysis, the Laplace transform is often used to represent time-domain signals in frequency-domain form. It should be noted that... (The text abruptly ends here, likely due to an incomplete sentence or missing information.) This represents the tracking signal of the piezoelectric reflector, which can be considered as... =0 indicates that the system does not perform related tracking.

[0047] Under ideal disturbance compensation conditions, when the numerator of the disturbance suppression transfer function is zero, complete suppression of load-side disturbances can be achieved, thus yielding the ideal expression for the disturbance feedforward controller:

[0048] (4)

[0049] in, , , These represent the piezoelectric constant, damping ratio, and natural frequency of the piezoelectric reflector. This is the cutoff frequency of the accelerometer.

[0050] Ignoring higher-order dynamic terms that may cause high-frequency amplification or system instability, the disturbance feedforward controller is decomposed into a multi-channel compensation structure based on angular acceleration, angular velocity, and angular displacement, as shown in the formula:

[0051] (5)

[0052] In the formula, Corresponding angular acceleration compensation channel, Corresponding angular velocity compensation channel, For the corresponding angular displacement compensation channels, each compensation channel adopts a parallel structure, such as... Figure 2 As shown in the dashed box, Indicates angular acceleration signal, Represents angular velocity signal, Indicates angular displacement signal, This indicates that the measured angular acceleration signal of the load platform is obtained by combining and processing the measurement signals from two linear accelerometers. The angular acceleration compensation channel is used to suppress mid-to-high frequency disturbances, the angular velocity compensation channel is used to suppress mid-frequency disturbances, and the angular displacement compensation channel is used to suppress low-frequency disturbances. Corresponding feedforward gain parameters are configured for each compensation channel to improve the system's broadband vibration detection capability.

[0053] Furthermore, in one embodiment, the present invention further includes:

[0054] The angular acceleration compensation channel is used to filter the measured angular acceleration signal through a bandpass filter to obtain the processed angular acceleration signal;

[0055] The angular velocity compensation channel is used to integrate the processed angular acceleration signal through a low-pass filter and then obtain the angular velocity signal through a high-pass filter.

[0056] The angular displacement compensation channel is used to integrate the obtained angular velocity signal through a low-pass filter to obtain the angular displacement signal.

[0057] Specifically, the calculated measurement angular acceleration signal Integration is performed. Due to inherent bias and noise in the accelerometer, direct integration may cause drift or even saturation in angular velocity and angular displacement. Therefore, the acceleration signal is first processed through a bandpass filter (BPF), and then a low-pass filter is used. The integration process is substituted to obtain the angular velocity signal, which is then processed by a high-pass filter (HPF). The HPF is placed in the angular velocity signal channel to filter out low-frequency drift and DC components introduced by accelerometer bias and low-frequency noise during integration, thereby avoiding accumulated errors in subsequent angular displacement calculations and improving the stability and accuracy of angular displacement estimation. A low-pass filter is then used subsequently. The integration is completed to obtain the angular displacement signal. Finally, the gain coefficient of the angular acceleration compensation channel is... Gain coefficient of angular velocity compensation channel Optimizations were made to enable the disturbance feedforward controller to effectively enhance the system's ability to suppress broadband disturbances without compromising the stability of the image closed loop.

[0058] In one embodiment, the process of iteratively optimizing the gain parameters of the initial multi-channel compensation structure to obtain the preset multi-channel compensation structure is as follows:

[0059] Input a disturbance signal of a first preset frequency, wherein the first preset frequency is in the mid-frequency band;

[0060] Based on the line-of-sight error signal of each round, the gain coefficient of the angular velocity compensation channel is successively corrected until the line-of-sight error converges.

[0061] After determining the gain of the angular velocity compensation channel, a disturbance signal of a second preset frequency is input, wherein the second preset frequency is in the high-frequency band;

[0062] Based on the line-of-sight error signal of each cycle, the gain coefficient of the angular acceleration compensation channel is successively corrected until the line-of-sight error converges, thus obtaining the multi-channel compensation structure.

[0063] Specifically, in the process of constructing a multi-channel compensation structure, a mid-frequency disturbance signal is first input into the system, and the gain coefficient of the angular velocity compensation channel is first adjusted. Make corrections and confirm. Then, the gain coefficient of the fixed angular velocity compensation channel. Then, a high-frequency disturbance signal is input into the system, and the gain coefficient of the angular acceleration compensation channel is adjusted. Make corrections, and determine the outcome after the line-of-sight error converges. Finally, a multi-channel compensation structure is obtained. It should be noted that the gain coefficient of the angular acceleration compensation channel can also be obtained by first inputting a high-frequency disturbance signal into the system. After making corrections, a mid-frequency disturbance signal is then input into the system to adjust the gain coefficient of the angular velocity compensation channel. Corrections are made. This invention does not specify the order of correction for particular gain coefficients. Ultimately... The optimized value is 0.8. The optimized value is 10. However, it should be noted that the optimized gain coefficient may vary depending on the platform hardware selection. It can be determined according to the actual situation.

[0064] In one embodiment, the invention further includes:

[0065] Determine whether the angular velocity and angular displacement signals obtained from the disturbance signal exhibit drift.

[0066] If drift occurs, then according to Determine the parameters of the integrator of the low-pass filter. And set the low-frequency cutoff frequency of the bandpass filter to The high-frequency cutoff frequency is set as the Nyquist frequency corresponding to the sampling frequency of the image sensor. The highest frequency among the low-frequency components that cause signal drift;

[0067] If no drift occurs, adjust the gain of the angular velocity compensation channel and the gain of the angular displacement compensation channel sequentially according to the frequency band of the disturbance signal.

[0068] Specifically, by observing the time-domain waveforms of the angular velocity and angular displacement signals, since the applied disturbance is a sinusoidal signal, the integrated angular velocity and angular displacement signals should theoretically maintain stable periodic sinusoidal waveforms. When the signal waveform is observed to shift upward or downward as a whole over time, or when the waveforms of adjacent periods no longer maintain stable periodic changes, it can be determined that signal drift has occurred.

[0069] If drift occurs, the integrated angular velocity and angular displacement signals are acquired, and their frequency components are analyzed using Fast Fourier Transform (FFT). Drift mainly originates from low-frequency noise and bias components of the linear accelerometer. These low-frequency components accumulate during integration, causing drift in the angular velocity and angular displacement signals. Let... The parameters of the low-pass filter integrator are the maximum frequency among the low-frequency components that cause signal drift. Determined according to the following relationship: By increasing the parameters This enhances the ability to suppress low-frequency drift. Simultaneously, the low-frequency cutoff frequency of the bandpass filter is set to... The high-frequency cutoff frequency is set to the Nyquist frequency corresponding to the image sensor's sampling frequency to further suppress low-frequency drift and prevent high-frequency noise from entering the system. For the filter parameters, the parameters of the low-pass filter's integrator are adjusted according to the above method. And the bandpass filter cutoff frequency, thereby improving the system's broadband disturbance suppression capability and tilt correction accuracy.

[0070] If no drift occurs, the feedforward gain coefficients of angular velocity and angular acceleration are adjusted sequentially according to the disturbance frequency band. In this embodiment, the image sensor sampling frequency is 200Hz, corresponding to a Nyquist frequency of 100Hz. Since the effective bandwidth of the image sensor closed-loop control is approximately 5Hz, 0-5Hz is divided into the low-frequency band; 5-30Hz, which falls between the closed-loop bandwidth and the first structural mode of the Stewart platform, is divided into the mid-frequency band; disturbances above 30Hz are divided into the high-frequency band. The low-frequency band receives the angular displacement feedforward signal, and the mid-frequency band receives the angular displacement and angular velocity feedforward signals, with the gain coefficients optimized. The system inputs three feedforward signals—angular displacement, angular velocity, and angular acceleration—in the high-frequency band and optimizes the gain coefficient. To ensure the accuracy of feedforward compensation, the system line-of-sight error is reduced by iteratively adjusting the feedforward channel gain and filter parameters.

[0071] In one embodiment, the step of successively correcting the angular velocity compensation channel gain based on the line-of-sight error signal for each round specifically includes:

[0072] Calculate the corresponding line-of-sight error evaluation index based on the line-of-sight error signal for each round;

[0073] The adjustment gradient is calculated based on the line-of-sight error evaluation index and the iteration step size.

[0074] The gain coefficient of the angular velocity compensation channel for the next round is calculated based on the adjusted gradient.

[0075] Specifically, after each round of disturbance suppression experiment, the feedforward channel gain and filtering parameters are successively corrected according to the magnitude of the line-of-sight error in the current round, and closed-loop control and measurement are repeated until the line-of-sight error converges or the compensation effect no longer improves significantly.

[0076] The line-of-sight error evaluation index after the k-th iteration is denoted as Among them, the line-of-sight error evaluation index can be the magnitude of the off-target amount of the CCD detection spot, and the feedforward gain parameter can be updated as follows:

[0077] , (6)

[0078] in, The iteration step size, This represents the gain coefficient of the angular acceleration compensation channel in the k-th iteration. This represents the gain coefficient of the angular acceleration compensation channel in the (k+1)th iteration. This represents the gain coefficient of the angular velocity compensation channel in the k-th iteration. This represents the gain coefficient of the angular velocity compensation channel in the (k+1)th iteration, where k represents the iteration number. The specific value can be set based on practical experience, such as 50 or 10. This indicates the adjustment gradient of the angular acceleration compensation channel; This indicates the adjustment gradient of the angular velocity compensation channel.

[0079] S104. Output the corresponding control quantity according to the compensated line-of-sight error signal to drive the piezoelectric reflector to produce a corresponding deflection, so that the target always stays in the center of the field of view.

[0080] Specifically, during system operation, the image sensor acquires target imaging information in real time and provides a line-of-sight error signal to the image closed-loop controller. The controller then outputs a control signal to drive the piezoelectric reflector to deflect accordingly, ensuring the target remains centered in the field of view. Simultaneously, a broadband perturbation is applied to the Stewart platform to simulate a complex vibration environment. A linear accelerometer mounted on the platform's load end measures the residual perturbation in real time and reconstructs the perturbation information with high precision. An image closed-loop circuit based on the piezoelectric reflector and image sensor is built on the Stewart platform's load end. The proportional-integral controller parameters are adjusted to meet the stability requirements of the tilt correction system. Meanwhile, the image closed-loop controller performs real-time automatic correction based on the detected line-of-sight error information.

[0081] This invention achieves real-time automatic correction of line-of-sight errors by constructing a closed-loop control system between a piezoelectric reflector and an image sensor at the load end of the Stewart platform. Secondly, residual disturbance signals at the platform load end are acquired using two linear accelerometers, and angular velocity and angular displacement are obtained by integrating angular acceleration using a low-pass filter instead of an integrator. Subsequently, a disturbance feedforward controller generates feedforward compensation signals through a multi-channel compensation structure, achieving segmented compensation for disturbances in different frequency bands, thereby improving the system's broadband vibration detection capability and tilt correction accuracy.

[0082] This invention overcomes the limitation of the system's closed-loop bandwidth, enabling rapid cancellation of disturbances and thus improving the system's anti-disturbance performance. The image sensor detects the residual displacement of the platform through a piezoelectric reflector optical system. By inputting the acceleration signal into the disturbance feedforward controller and coordinating with the position closed-loop control system, the influence of mid-to-high frequency disturbances on the platform is effectively suppressed, thereby improving the system's broadband disturbance suppression capability and tilt correction accuracy.

[0083] This invention also provides a correction system corresponding to the method embodiments described above. Since the system embodiments are basically similar to the method embodiments, the description is relatively simple. For details of the relevant technical features and their effects, please refer to the corresponding descriptions of the method embodiments provided above. This invention provides a line-of-sight tilt correction system based on broadband vibration detection using a linear accelerometer, such as... Figure 3 As shown, the system specifically includes:

[0084] The Stewart platform, piezoelectric reflector, image sensor, first-line accelerometer (accelerometer 1), second-line accelerometer (accelerometer 2), disturbance feedforward controller, and image closed-loop controller;

[0085] The image sensor is used to obtain a line-of-sight error signal based on the acquired target imaging information;

[0086] The first and second linear accelerometers are used to collect disturbance signals from the load end of the Stewart platform in real time. The first and second linear accelerometers are installed symmetrically on the load end of the platform, and the sensitive axes of the two linear accelerometers are parallel and opposite. The disturbance signal is the angular acceleration signal of the load Stewart platform motion synthesized from the acceleration data in different directions obtained by the first and second linear accelerometers.

[0087] The disturbance feedforward controller is used to obtain a feedforward compensation signal by superimposing the disturbance signal through a preset multi-channel compensation structure and to perform feedforward compensation on the line-of-sight error signal.

[0088] The image closed-loop controller is used to output a corresponding control quantity based on the compensated line-of-sight error signal to drive the piezoelectric reflector to produce a corresponding deflection, so that the target always remains in the center of the field of view.

[0089] This invention also provides an electronic device, which includes a processor and a memory. The memory stores at least one instruction or at least one program, which is loaded and executed by the processor. The method described above provides a line-of-sight tilt correction method based on broadband vibration detection using a linear accelerometer.

[0090] Furthermore, the electronic device may participate in or include the apparatus or system provided in the embodiments of this application. The electronic device may include one or more processors (processors may include, but are not limited to, processing devices such as microprocessors (MCUs) or programmable logic devices (FPGAs), memory for storing data, and transmission devices for communication functions. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a power supply, and / or a camera.

[0091] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuit may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the device (or mobile device). As involved in the embodiments of the present invention, the data processing circuit serves as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0092] The memory can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the method described in the embodiments of this application. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, thereby realizing the above-mentioned data processing method. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to electronic devices via a network. Examples of the above-mentioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0093] The transmission device is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the device's communication provider. In one example, the transmission device includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device may be a Radio Frequency (RF) module, used for wireless communication with the Internet.

[0094] The display can be, for example, a touchscreen liquid crystal display (LCD), which allows users to interact with the user interface of an electronic device (or mobile device).

[0095] This invention also provides a computer storage medium storing at least one instruction or at least one program, which is loaded and executed by a processor to implement the line-of-sight tilt correction method based on broadband vibration detection of a linear accelerometer provided in the above-described method embodiments.

[0096] Optionally, in this embodiment, the aforementioned computer storage medium may be located at at least one of the multiple network servers in a computer network. Optionally, in this embodiment, the aforementioned storage medium may include, but is not limited to, various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0097] This invention also provides a computer program product or computer program, which includes computer instructions stored in a computer storage medium. The processor of an electronic device reads the computer instructions from the computer storage medium and executes the computer instructions, causing the electronic device to perform the line-of-sight tilt correction method based on broadband vibration detection using a linear accelerometer provided in the above-described method embodiment.

[0098] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0099] It should be understood that the above description of the preferred embodiments is quite detailed, but it should not be considered as a limitation on the scope of protection of this invention. Those skilled in the art, under the guidance of this invention, can make substitutions or modifications without departing from the scope of protection of the claims of this invention, and all such substitutions or modifications fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.

Claims

1. A method for line-of-sight tilt correction based on broadband vibration detection using a linear accelerometer, characterized in that, The method includes: The image sensor obtains the line-of-sight error signal based on the acquired target imaging information; The disturbance signal at the load end of the Stewart platform is acquired in real time by a first linear accelerometer and a second linear accelerometer. The first and second linear accelerometers are installed symmetrically at the load end of the platform, and the sensitive axes of the two linear accelerometers are parallel and opposite. The disturbance signal is a measurement angular acceleration signal of the load Stewart platform motion synthesized by the acceleration data in different directions acquired by the first and second linear accelerometers. Based on the disturbance signal, the disturbance feedforward controller performs signal superposition through a preset multi-channel compensation structure to obtain a feedforward compensation signal and performs feedforward compensation on the line-of-sight error signal. Based on the compensated line-of-sight error signal, the corresponding control quantity is output to drive the piezoelectric reflector to produce a corresponding deflection, so that the target always remains in the center of the field of view.

2. The method according to claim 1, characterized in that, The process of generating the measured angular acceleration signal includes: Obtain the measurement output results of the first linear accelerometer and the second linear accelerometer; The angular acceleration signal is calculated based on the measurement output and the distances between the first and second linear accelerometers and the center of the inertial reference frame, wherein the distances between the first and second linear accelerometers and the center of the inertial reference frame are the same.

3. The method according to claim 2, characterized in that, The step of generating a feedforward compensation signal by superimposing signals through a preset multi-channel compensation structure based on the disturbance signal and then performing feedforward compensation on the line-of-sight error signal includes: Based on the frequency band of the disturbance signal, the corresponding compensation channel is selected to generate a feedforward compensation signal and perform feedforward compensation on the line-of-sight error signal.

4. The method according to claim 3, characterized in that, The preset multi-channel compensation structure includes an angular acceleration compensation channel, an angular velocity compensation channel, and an angular displacement compensation channel, and the three compensation channels are connected in parallel. The step of selecting the corresponding compensation channel to generate a feedforward compensation signal and performing feedforward compensation on the line-of-sight error signal according to the frequency band of the disturbance signal includes: When the disturbance signal is in the high-frequency band, the superposition signal of the angular acceleration signal generated by the angular acceleration compensation channel, the angular velocity signal generated by the angular velocity compensation channel, and the angular displacement signal generated by the angular displacement compensation channel is used as the feedforward compensation signal; When the disturbance signal is in the mid-frequency band, the superposition signal of the angular velocity signal generated by the angular velocity compensation channel and the angular displacement signal generated by the angular displacement compensation channel is used as the feedforward compensation signal. When the disturbance signal is in the low frequency band, an angular displacement signal is generated through the angular displacement compensation channel and used as a feedforward compensation signal.

5. The method according to claim 4, characterized in that, The method includes: The angular acceleration compensation channel is used to filter the measured angular acceleration signal through a bandpass filter to obtain the processed angular acceleration signal; The angular velocity compensation channel is used to integrate the processed angular acceleration signal through a low-pass filter and then obtain the angular velocity signal through a high-pass filter. The angular displacement compensation channel is used to integrate the obtained angular velocity signal through a low-pass filter to obtain the angular displacement signal.

6. The method according to claim 1, characterized in that, The pre-defined multi-channel compensation structure construction process includes: Based on the dynamic relationship between the disturbance signal and the line-of-sight error signal at the Stewart platform load end, a disturbance suppression transfer function is established; The initial multi-channel compensation structure is obtained based on the disturbance suppression transfer function, wherein when the disturbance suppression transfer function is zero, complete suppression of disturbances at the load end of the Stewart platform is achieved. The gain parameters of the initial multi-channel compensation structure are iteratively optimized to obtain a preset multi-channel compensation structure.

7. The method according to claim 6, characterized in that, The step of iteratively optimizing the gain parameters of the initial multi-channel compensation structure to obtain the preset multi-channel compensation structure includes: Input a disturbance signal of a first preset frequency, wherein the first preset frequency is in the mid-frequency band; Based on the line-of-sight error signal of each round, the gain coefficient of the angular velocity compensation channel is successively corrected until the line-of-sight error converges. After determining the gain of the angular velocity compensation channel, a disturbance signal of a second preset frequency is input, wherein the second preset frequency is in the high-frequency band; Based on the line-of-sight error signal of each cycle, the gain coefficient of the angular acceleration compensation channel is successively corrected until the line-of-sight error converges, thereby obtaining the preset multi-channel compensation structure.

8. The method according to claim 7, characterized in that, The step of successively correcting the angular velocity compensation channel gain based on the line-of-sight error signal for each cycle includes: Calculate the corresponding line-of-sight error evaluation index based on the line-of-sight error signal for each round; The adjustment gradient is calculated based on the line-of-sight error evaluation index and the iteration step size. The gain coefficient of the angular velocity compensation channel for the next round is calculated based on the adjusted gradient.

9. The method according to claim 8, characterized in that, The method further includes: Determine whether the angular velocity and angular displacement signals obtained from the disturbance signal exhibit drift. If drift occurs, the parameters of the low-pass filter integrator are determined based on the maximum frequency of the low-frequency component that causes the signal drift, and the low-frequency cutoff frequency of the band-pass filter is set to the maximum frequency of the low-frequency component that causes the signal drift, and the high-frequency cutoff frequency is set to the Nyquist frequency corresponding to the sampling frequency of the image sensor. If no drift occurs, adjust the gain of the angular velocity compensation channel and the gain of the angular displacement compensation channel sequentially according to the frequency band of the disturbance signal.

10. A line-of-sight tilt correction system based on broadband vibration detection using a linear accelerometer, characterized in that, The system includes: a Stewart platform, a piezoelectric reflector, an image sensor, a first-line accelerometer, a second-line accelerometer, a disturbance feedforward controller, and an image closed-loop controller; The image sensor is used to obtain a line-of-sight error signal based on the acquired target imaging information; The first and second linear accelerometers are used to acquire disturbance signals from the load end of the Stewart platform in real time. The first and second linear accelerometers are installed symmetrically on the load end of the platform, and the sensitive axes of the two linear accelerometers are parallel and opposite. The disturbance signal is a measurement angular acceleration signal of the load Stewart platform motion synthesized from acceleration data in different directions acquired by the first and second linear accelerometers. The disturbance feedforward controller is used to obtain a feedforward compensation signal by superimposing the disturbance signal through a preset multi-channel compensation structure and to perform feedforward compensation on the line-of-sight error signal. The image closed-loop controller is used to output a corresponding control quantity based on the compensated line-of-sight error signal to drive the piezoelectric reflector to produce a corresponding deflection, so that the target always remains in the center of the field of view.

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